Air flow systems used in residential and commercial structures typically include a single thermostat connected to a central heating and/or air conditioning system. Air is received through an intake vent, heated or cooled, then circulated through one or more rooms via a fan connected to an air duct system. In each room or zone of the structure there is one or more vents or registers connected to the air duct system than can be manually opened or closed by moving a mechanical lever on the register. The registers are typically located in the floor or on the ceiling.
A major drawback of conventional air flow systems is the inability to efficiently heat or cool all zones to a target temperature. For example, when the zone that contains the thermostat reaches the target temperature, the air flow system is turned-off, even if all of the other zones have not yet reached the target temperature. Rooms located on the opposite side of the structure or on another floor may be significantly cooler or warmer than the room containing the thermostat.
While some systems allow the air flow system to be manually turned on by the occupant (e.g., disconnected from the thermostat), this technique consumes energy and requires the occupant to examine each room to see if the desired temperature has been reached before turning off the air flow source. Clearly, this is an impractical solution for structures with many zones or for occupants with physical disabilities.
Registers can also be used to control air flow into a room. If a particular room is too hot or too cold, the register can be manually closed using a mechanical lever to prevent the air from entering the room. Registers, however, are not always accessible because of their location (e.g., on the ceiling) or because they are obstructed (e.g., in the floor and covered by heavy furniture). Moreover, the opening and closing of a register may have to be performed several times a day to maintain the desired room temperature due to leakage from imperfect insulation or occupants leaving and entering the room.
Another problem typically found with residential systems is the inability to automatically heat or cool rooms to different target temperatures. Individuals have different sensitivities to temperature. Thus, by heating or cooling all rooms to the same temperature, some of the occupants may find the target temperature to be uncomfortable.
Accordingly, there is a need for an automated air flow system and method of heating or cooling zones of a structure to one or more target temperatures without having to manually open or close registers. Such a system and method should be energy efficient by controlling the air flow source to heat or cool selected zones until the one or more target temperatures are reached.